The present invention relates to a developing apparatus of an electrophotographic equipment such as an electrophotographic copying machine and more particularly to a developing apparatus wherein a developer container having therein a magnetic brush carrier and a developer replenishing container are united in one.
For developing electrostatic latent images formed on the image carrier such as a photoreceptor in the form of a drum or a belt in an electrophotographic equipment such as an electrophotographic copying machine, for example, there is generally and widely used a developing apparatus wherein a magnetic developer such as a single-component developer consisting only of magnetic toner or a two-component developer consisting of magnetic carrier and non-magnetic toner is used and a magnetic feeder that conveys aforesaid developer in the form of a brush formed thereon by magnetic effect thereon to the developing area is provided. (Whereinafter the magnetic feeder is called as a magnetic brush carrier.)
Aforesaid developing apparatus is required to be equipped with a developer container having a magnetic brush carrier and with a developer replenishing container having a means for replenishing developer to aforesaid developer container and to be constituted so that aforesaid means for replenishing developer is actuated depending on the amount of developer or toner concentration both in the developer container. The developing apparatus is further required to be small in size, light in weight and simple in structure for the easy maintenance or the quick attaching and detaching operations. In aforesaid developing apparatus, however, it is difficult to make it small in size, light in weight and simple in structure because the developer replenishing container is provided on the upper portion of the developer container so that the supplying port through which the developer is replenished is positioned above the bottom of the developer container and, in addition to that, a developer-distributing means is provided on the developer replenishing container or on the developer container so that the developer can be replenished evenly in the direction of the axis of the magnetic brush carrier. The developing apparatus disclosed in Japanese Patent Examined Publication No. 42389/1980, for example, will be explained next. Aforesaid developing apparatus is so constructed that a developer container and a developer replenishing container are united in one body, wherein the developer container has a magnetic brush carrier and the developer replenishing container has both a screw for the use of developer-conveyance and a ratchet wheel for replenishing a predetermined amount in which the screw and the ratchet wheel both are arranged in parallel to aforesaid magnetic brush carrier. Further, the developing apparatus is so constituted that, the developer in a developer supplier provided at the upper portion on one end of the developer replenishing container is supplied to the developer replenishing container by means of the screw for the use of developer-conveyance and a screw cover, wherein the screw cover is arranged at front side along the direction of the axis of aforesaid screw and has a tapered top face that gradually reduces its dimension in the proceeding direction of the screw so that the developer is evenly dispersed in the direction of the axis of the screw. For replenishing a predetermined amount of the developer to the developer container, the ratchet wheel provided at the supplying port of the developer replenishing container positioned above the bottom of the developer container is rotated. Aforesaid developing apparatus is capable of replenishing the developer into the developer container while dispersing the developer uniformly in the axial direction of the magnetic brush carrier, but it has disadvantages that the constitution for aforesaid uniform dispersion is complicated and the developing apparatus itself tends to be bulky in the vertical direction because the developer replenishing container is located at the upper portion of the developer container. Thus the maintenance or mounting and dismounting operations of the developing apparatus is not easy and is not satisfactory for practical use.